kvasilak / gmcwiper

GMCWiper

A windshield wiper upgrade for the classic GMC motorhome.
The GMC has a really cool hydraulic, variable speed wiper motor.
What it doesn't have is intermittentness.
and when you run the wipers real slow, they shudder and shake and do strange things.
The speed is controlled by a 35 year old cable and is hard to adjust.

This controller uses a hobby servo to both set the speed and implement intermittent wipers.
It also causes 2 sweeps of the wipers if the user presses the mist button with the wipers off or in intermmittent mode.

The hardware consists of the following;

1. The stated hobby servo that is connected to the wiper motor valve via a control rod.
   The servo is used to adjust the wiper speed for both speed and intermittent settings.
   
2. There is a parked switch that senses when the wipers have returned to the down position.
   The parked switch allows the controller to know when to start the delay timer.
   The parked switch is not used in speed mode.
   With out the park switch it's impossible to know when to start the next sweep as sweep time is dependant on
   engine speed, windshield wetness etc.
   
3. An on/off/on switch used to select speed vs wiper mode or off.
   This allows 1 switch to select 3 different modes using 2 input lines.
   
4. A linear pot that replaces the speed adjustment lever of the original system.
   No requirement to be a linear pot except for appearance.
   
5. A push button used for the mist button. Pressing this button causes the wipers to make 2 sweeps.
   This button can be triggered off the windshield washer button with a relay etc if desired
   
6. An arduino microcontroller to read all the inputs and control the servo. This project uses the 5v 16mhz Pro mini,
   But there is no reason other implementations cannot be used.
   
7. A power supply with enough power to run the Arduino and the servo motor.
   I used a $2 ebay adjustable power supply with a 35 volt input rating. I set it to 6 volts to run the servo and use the internal mini pro regulator for the processor